"Tanned skin is damaged skin." "Imagine that your skin normally begins to burn after 10 minutes in full sun without any protection. A 30 SPF sunscreen would provide 30 times the protection of no sunscreen." That means 30 times longer before you start to burn, or in this case, 300 minutes.
Regarding this, which SPF sunscreen is best?
SPF 30 is the most common level for most people and skin types. No sunscreen can block all UV rays, but what we do know is: SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97% of UVB rays and SPF 50 blocks 98% of UVB rays.
What does 70 mean on sunscreen?
SPF 30 means 97% of UVB rays are blocked. SPF 50 means 98% of UVB rays are blocked. SPF 70 means 98.5% of UVB rays are blocked. SPF 100 means 99% of UVB rays are blocked. Notice that once you hit an SPF of 10 then 90% the percent of UVB rays blocked.
What does 100 mean on sunscreen?
The number doesn't indicate how long a person can be outside in the sun before suffering from a burn. To give you an idea of what the numbers mean, an SPF 15 sunscreen blocks 94 percent of UVB rays, SPF 30 blocks 97 percent, SPF 50 blocks 98 percent, and SPF 100 blocks 99 percent.